The following publications relate to the synthesis of TCNQ and to various synthetic steps relevant to the practice of the present invention. The publications, which are referenced by number throughout the specification, are incorporated herein by reference.
1. J. H. Perlstein, Angew. Chem. Int. Ed. Engl., 16, 519 (1977). PA0 2. Z. G. Soos, J. Chem. Education, 55, 546 (1978). PA0 3. A. J. Fatiadi, Synthesis, 241 (1978). PA0 4. D. S. Acker and W. R. Hertler, J. Am. Chem. Soc., 84, 3370 (1962). PA0 5. A. T. Nielsen and W. R. Carpenter, Org. Syn. Coll. Vol. V, p. 288. PA0 6. H. Adkins and H. R. Billica, J. Am. Chem. Soc., 70, 695 (1948). PA0 7. U.S.S.R. Patent 436,044; Chem. Abstr., 81, 151638 (1974). PA0 8. Japanese Patent 7006009; Chem. Abstr., 72, 132156 (1970). PA0 9. Japanese Patent 7016097; Chem. Abstr., 73 124007 (1970). PA0 10. W. Kern, W. Gruber, and H. O. Wirth, Makromol. Chem., 37, 198 (1960); Chem. Abstr., 55, 7349 (1961). PA0 11. I. Motoyama, Nippon Kagaku Zasshi, 79, 1296 (1958); Chem. Abstr., 54, 5552 (1960). PA0 12. J. Lichtenberger and J. Hincky, Bull. Soc. Chim. France, 354 (1961); Chem. Abstr., 55, 19821 (1961). PA0 13. S. Fujita, Mem. Coll. Sci. Kyoto Imp. Univ., 23A, 405 (1942); Chem. Abstr., 44, 3445 (1950). PA0 14. L. N. Owen and P. A. Robins, J. Chem. Soc., 320 (1949); Chem. Abstr., 43, 7435 (1949). PA0 15. R. C. Olberg, H. Pines, and V. N. Ipatieff, J. Am. Chem. Soc., 66, 1096 (1944); Chem. Abstr., 38, 4913 (1944). PA0 16. K. Dimroth, Chem. Ber., 72B, 2043 (1939); Chem. Abstr., 34, 3242 (1940). PA0 17. L. Palfray, Bull. Soc. Chim. France, 7, 407, (1940); Chem. Abstr., 36, 2838 (1942). PA0 18. C. J. Gogek, R. Y Moir, and C. B. Purves, Can. J. Chem., 29, 946 (1951). PA0 19. J. C. Sircar and A. I. Meyers, J. Org. Chem., 30, 3206 (1965). PA0 20. S. Wolfe, S, K, Hasan, and J. R. Campbell, Chem. Communications, 1420 (1970). PA0 21. P. Mussini, F. Orsini, and F. Pelizzoni, Synthetic Communications, 5, 283 (1975). PA0 22. Japanese Patent 7616643; Chem, Abstr., 85, 32525 (1976). PA0 23. J. Vene, Bull. Soc. Sci. Bretagne, 20, 11 (1945); Chem, Abstr., 41, 4111 (1947); ibid., 23, 123 (1948); Chem. Abstr., 44, 6395 (1950). PA0 24. A. J. Fatiadi, Synthesis, 165 (1978).
Although an overall synthesis of 1,4-bis(dicyanomethylene)cyclohexane from hydroquinone has not been proposed or conducted previously, it is possible to construct such a synthesis by using methods from the above literature for each of the three individual steps. Choosing three of the best procedures for which experimental details are available (Refs. 18, 21, 4), this synthesis would afford the desired compound in ca. 85% overall yield from hydroquinone. But, this synthesis, reconstructed from the art-disclosed reactions, would require the use of three different solvents (alcohol, acetone, and water) with consequent need for isolation of intermediates at each stage.
In contrast, the entire synthesis scheme of the present invention involves three chemical reaction steps with combined reaction times totalling approximately one hour. The only other processing steps are two catalyst filtrations and the filtration of the final product. No organic solvents or solvent extraction steps are used at any point. The preferred Raney nickel and ruthenium oxide catalysts that are recovered can be reprocessed and used again.